An example of an electric contact coupling for automatic central buffer couplings is known from the EP 0 982 215 B1 printed publication which provides for an electrical cable coupling to be retained in longitudinally-displaceable fashion on a mechanical central buffer coupling. This known cable coupling comprises at least one plug-and-socket connection connected via a connection line arranged on the respective side of a coupling's point of separation for couplable rail vehicles. In order to avoid a redundant contact arrangement disposed symmetrically to the vertical central longitudinal plane of the coupling rod and to be able to configure the cable coupling as a whole in a simpler and lighter manner, the cable coupling according to this prior art furthermore comprises a longitudinally-displaceable adapter box which is arranged between the respective plug-and-socket connections of the rail vehicle in the coupled state and on only one of the respective plug-and-socket connections in the uncoupled state. This adapter box contains the necessary electric connection lines for connecting the connection lines of the rail vehicles to be coupled.
Moreover known from the DE 199 26 085 A1 printed publication, for example, is an electric contact coupling for automatic central or central buffer couplings which has a contact plate comprising contacts for electric connections affixed at the coupling head and displaceable in the longitudinal direction of the central buffer coupling. In order to protect the contact for the electric connections to the greatest extent possible, this prior art also known from the field of rail-borne vehicle technology provides for the contact plate to be displaceable from a rear, uncoupled position into a forward, couple-ready position, wherein the contact plate is covered by a protective cap in the rear position and is uncovered in the forward position by the protective cap being pivoted away.
The fundamental problem with such known systems for transmitting discrete control signals and data signals is the strong mechanical load brought to bear on the electrical contacts used, in particular while coupling. Due to the coupling procedures, which are usually automated, but also due to vibrations and attrition during operation as well as atmospheric effects, conventional signal transmission systems normally used in couplings suffer progressive contact damage. Especially the contact terminals are subject to a considerable degree of wear and corrosion. Among other things, one consequence of this is that the electrical resistance of the electric contacts increases during signal transmission which impairs the quality of the signals to be transmitted and in extreme cases can even lead to the complete loss of the signal connection.
In order to ensure problem-free signal transmission, conventional signal transmission systems therefore require regular maintenance and inspection of the contacts provided in the electric coupling. Required in particular is the regular cleaning and replacement of the electric contact terminals used in the electrical or mechanical coupling.
One possibility of circumventing these problems associated with the conventional transmission of discrete control signals and data signals could, for example, consist of greatly reducing the number of single signal contact terminals used in an electrical contact coupling, which can be done for instance by bundling a plurality of single signal contact terminals or by using a multiplex operation as known per se. While such a solution allows for a lesser total outlay of the wiring necessary for an individual electrical contact coupling such that the electrical contact coupling itself can also be configured smaller if need be, it does not eliminate the fundamental problem of the extreme mechanical load brought to bear on the electrical contacts used as arises during the coupling procedure. Here as well, the electrical contacts are subject to major mechanical load and attrition, especially while being coupled.
Known further from the DE 10 2004 037 849 A1 printed publication is a rail coupling device having a first train coupling and a second train coupling, each connected to the respective car body of a rail-borne vehicle by means of a car attachment. A transmission system which functions without contact for transmitting audio signals, video signals, operational data, commands and/or other bus data is provided between the first rail vehicle and the second rail vehicle. Specifically, the transmission system consists of a first HF component, a second HF component, a first transmitting/receiving device and a second transmitting/receiving device. The HF components are affixed to or in the train coupling, preferably on the side at which the coupling is disposed. The antenna members provided in the signal transmission device as known from the art are each configured as a patch antenna, and in particular as a surface-mountable miniature ceramic antenna.
The disadvantage to this known solution, however, is especially seen as being the low quality to the data transmission. In particular, a patch antenna as the conventional solution suggests is only conditionally suited to non-contact data transmission in an automatic central buffer coupling since the total attenuation of the signal transmission system is relatively high. This makes selecting an accordingly high transmission level for the respective patch antenna imperative. Yet due to the patch antenna's unfavorable radiation pattern, a relatively high transmission level leads to high antenna member interference emissions.
A further disadvantage to the known solution of the prior art is seen in the fact that the patch antennas' immunity to noise; i.e., the irradiation pattern of external background radiation, is also inadequate in the proposed patch antenna configuration. In practical use, such circumstances with this type of signal transmission system can at times only dictate an unreliable and interference-prone data transmission.
Based on the given disadvantages and problems associated with conventional signal transmission systems in couplings, the present invention addresses the task of optimizing an automatic central buffer coupling according to DE 10 2004 037 849 A1 such that data transmission with the signal transmission device functions more reliably and particularly invulnerable to interference, also in particular given low transmitting power with the antenna members utilized.